The easiest way to know how much fluid is to weigh yourself before and after running. If you are one lb less you need 16 oz of water, etc.

Those sports drinks were designed to replace the fluid losses of sweat, so you can use the low cal Gatorade or powerade if you want to replace salt. Thre are recipes (google search) to make your own drinks too.

In reality though, if you just listen to your own sense of thirst and craving for salt, you will be fine. The body is marvelous at regulating exact how much sodium and water to retain or to excrete from the kidneys. Most people far overeat the daily requirements of sodium and your kidneys just pee it out, so yours will likely have no problem retaining some if needd.

I have problems with dehydration sometimes and exercise is not the particular issue as mine is fairly non strenuous. I do drink lots of water but it seems to go right through me leaving me the same. What helps me more is to eat more salad, some raw veggies. Maybe water in them is absorbed better? Anyway, just throwing that out there in case it helps.

I'm a water drinker by nature, but we all have those days where it's harder to get it in. On those days, I keep a glass in the bathroom and drink a full glass of water every time I go to the bathroom. I know it seems weird, but it really helps. Maybe there's a new habit you can form that works with your runs?

Could you make a system to remind yourself to hydrate maybe 15-20 minutes before your run, so it's not sloshing around in there, and maybe drink a glass right after you shower? Figure out some part of your pre- and post-run routine where you can get liquids in without feeling ill, and how to make it easy to remember.

I use Emergen-C Electro Mix. It's 0 carbs and adds a nice lemon flavor to your water. I find it works really nice on long runs. Netrition doesn't seem to carry it, but you can get it online from the big marketplace, and if you subscribe and save with it, you can get it shipped alone even though it's an "addon item" that would normally require $25 minimum.

My favorite is Powerade Zero strawberry. It comes in a 32 oz bottle that I put in the freezer before I head out to let it get slushie. If it is warm (60+) or I run more than 5 miles I drink the whole thing over the hour or so after I come in. Then water or tea or whatever the rest of the day.

I mostly just drink to thirst, but make an effort to replace electrolytes. If I don't I will cramp up like the dickens at night.

The easiest way to know how much fluid is to weigh yourself before and after running. If you are one lb less you need 16 oz of water, etc.

Those sports drinks were designed to replace the fluid losses of sweat, so you can use the low cal Gatorade or powerade if you want to replace salt. Thre are recipes (google search) to make your own drinks too.

In reality though, if you just listen to your own sense of thirst and craving for salt, you will be fine. The body is marvelous at regulating exact how much sodium and water to retain or to excrete from the kidneys. Most people far overeat the daily requirements of sodium and your kidneys just pee it out, so yours will likely have no problem retaining some if needd.

Spot on and pretty easy to do a test. Your sweat rate will change based on outside factors so keep in mind weather conditions and effort, often stated as RPE (Rate of Perceived Effort) on a scale of 1-10. Their are often other influences including diet and fitness level at time of test but those are typically captured by using the RPE Scale.

With this in mind you can do a test on a short run with no fluids during or electrolyte replacement during. Weigh yourself just prior to heading out naked. Then go for a 30 minute run. When you return you can take off your running gear and clothes, towel off and weigh again.

Note the difference and assuming that 16 oz of water weighs 1 pound you can get a rough idea of your sweat rate. If you drop 2 lbs then your sweat rate is 16 oz each 15 minutes given the conditions that you noted, say 85 degrees and RPE 5 (Moderate Effort).

Obviously it would be difficult and possibly dangerous to try and replenish all of your lost fluids immediately on returning so just drink extra and your good to go. If you feel weak or nauseated you might consider taking a salt tablet or two during or right after. Just a pill that is loaded with electrolytes and no sugar. Salt stick makes a brand that I use and prefer.

Sorry for the long reply

__________________Racing is a lot like wrestling a gorilla, you don't stop when you get tired you stop when the gorilla gets tired